Python article in Hakin9 Magazine

Patrycja  Przybylowicz, the fine editor of the Hakin9 Magazine, contacted me some days ago letting me know that my article about using Encrypted Python modules with Import Hooks, was going out in the October, 2011 issue.

Well, that issue is now out and you can see the preview here: http://hakin9.org/hack-apple-1011

I'm pretty happy about this, I've always loved that magazine and being part of it, its a great deal for me.

Django Dia exporter

Today, I adapted an old piece of code I had laying around in my personal GIT. I wrote this code some time ago when I needed to transform an UML diagram I designed, using the awesome DIA, into a Django models file.

All you need to do is take this code and put it somewhere in ${DIA_SHARE_FOLDER}/python/codegen.py (where DIA_SHARE_FOLDER is generally /usr/share/dia), add an import re at the beginning of that file and this:

dia.register_export ("PyDia Code Generation (Django)", 

"py", DjangoRenderer()) 

at the very end (together with the other generators).

The code is:

class DjangoRenderer(ObjRenderer) :
   
    mapp = {"Datetime" : "DateTime"}

    def __init__(self) :

        ObjRenderer.__init__(self)
        self.processed_kls = set([])

    def end_render(self) :
        re_foreign = re.compile(r"[cC]lass\s*(.*).*")
        field_str = "\t%s = models.%sField(%s) %s\n"
        foreign_str = "\t%s = models.ForeignKey('%s'%s) %s\n"

        f = open(self.filename, "w")
        f.write("from django.db import models %s" % ("\n" * 3))
        for sk in self.klasses.keys() :
            parents = self.klasses[sk].parents + self.klasses[sk].templates
            f.write ("class %s (models.Model):\n" % (sk,))
            
            kls_attributes = dict(self.klasses[sk].attributes)
            attributes = kls_attributes.keys()

            if attributes.__len__() == 0:
                f.write("\tpass\n\n")
            else:
                for sa in attributes :

                    comments = ""

                    attr = kls_attributes[sa]
                    value = attr[2] == "" and "None" or attr[2]
                    comments = attr[3]

                    if attr[3]:
                        comments = "#%s" % attr[3].replace('\n', ' ')
                    try:
                        ty, parms = [x.strip() for x in attr[0].split("|")]
                    except ValueError:
                        ty, parms = (attr[0], "")

                    mobj = re_foreign.match(ty)

                    if mobj:
                        foreign_obj = mobj.groups()[0]
                        f.write(foreign_str % (sa, foreign_obj, 

parms, comments))
                    else:
                        ty = ty.capitalize()
                        ty = self.mapp.get(ty, ty)
                        f.write(field_str % (sa, ty, parms, comments))
                else:
                    f.write("\n" * 2)
        f.close()
        ObjRenderer.end_render(self)

Now. The only thing to take into consideration is, when designing in DIA, you have to be a bit more specific in the Type of properties of your classes.

For instance. If you want a property to be of type string, you should specify it as:

Char | max_length=200, null=True.

This tells the exporter that it should construct a

models.CharField(max_length=200, null=True)

If you want to specify a ForeignKey, the type should be:

Class SomeClass

or if you have options (like related_name), this should be:

Class SomeClass | related_name=some.

Hope this serves you somehow.